To perform a variety of radioimmunoassays for protein, peptides, and steroid hormones in tissues and biological fluids of laboratory animals. In addition, the laboratory will provide radioiodinated, purified preparations of protein and peptide hormones suitable for use in radioimmunoassays. These assays will be used in support of the studies of neuroendocrine regulation of fertility and gonadal function being carried out by the Reproductive Neuroendocrinology Section of the LRDT at NIEHS.